This invention relates to filter systems, and in particular to a filter system particularly useful for reconditioning water-soluble coolants.
Metalworking oils are used in industries as diverse as machine shops and machinery manufacturing. Water-based cooling and lubricating oils are routinely sprayed into metal-cutting and shaping equipment. Because the oils, especially in water-soluble coolant form, are generally recaptured and recycled, they often end up containing a mixture of bacteria and other contaminates that increase machine operator health risks and corrode machinery. Because machines often spray coolants into the ambient area both in droplet form and vapors, all parts of the machinery are adversely affected. Also, it is common for machine operators to experience chronic dermatitis and lung problems from biological growth in water-soluble machine coolants. Historically, machine operators have tried to protect themselves with gloves and masks. Generally, this has not been practical. Another solution has been to add chemical agents formulated to kill bacteria to the coolant. However, bactericides are themselves harsh and toxic, presenting other dangers to machine operators. To protect machinery and machine operators, coolants must be frequently changed. This raises other problems involving disposal of bacteria-contaminated coolant as well as cost to frequently replace coolant.
Economically speaking, the most important metal-corroding and coolant-destroying microbe are the anaerobic, sulfate-reducing bacteria. These bacteria produce hydrogen sulfides, which react with iron, corrode metals and destroy coolants.